The invention relates to a method for preserving the stability of a hemoglobin blood substitute comprising maintaining the hemoglobin blood substitute in an atmosphere substantially free of oxygen. The method for preserving the deoxygenated hemoglobin blood substitute comprises maintaining the deoxygenated blood substitute in an oxygen barrier film overwrap package, wherein at least one face of the overwrap package comprises a transparent laminate material and wherein at least one other face of the overwrap package comprises a foil laminate material. The preserved deoxygenated hemoglobin blood substitute comprises a deoxygenated hemoglobin blood substitute and an oxygen barrier film overwrap package wherein at least one face of the overwrap package comprises a transparent laminate material and wherein at least one other face of the overwrap package comprises a foil laminate material.